Tower Defense Meets Vampire Survivors (and Everything Is a Placeholder)

I've been building a game that can't decide whether it's Bloons TD or Vampire Survivors, so it just does both at once. Working title: td-survivors (also a placeholder, more on that in a second). Enemies walk a fixed path, you drop towers beside it, and while all that is happening you're also collecting XP orbs, leveling up, and picking upgrade cards like it's a whole other genre. Because it is. This is post one of a series where I take that idea apart in public.

If you've read anything here before, it was about a different game of mine, Memory Falling Into Place, a bullet-hell roguelike about a ship trapped in a cube. This is not that. Different engine, different genre, different pile of bugs. Fresh start.

The pitch, in one breath

Take the skeleton of a Bloons game: a fixed path snaking across the map, enemies marching along it in waves, and you planting towers next to the path to shoot them before they reach the end. Every enemy that does reach the end costs you a life. You start each stage with 30 lives, and when you hit zero it's game over and an instant restart, no ceremony.

Now graft Vampire Survivors onto that skeleton. Killed enemies drop XP orbs. Fill the XP bar and the whole game freezes and hands you 3 upgrade cards. Pick one, the game unfreezes, and you're a little stronger than you were four seconds ago. That freeze-and-choose beat is the beating heart of the survivors genre, and dropping it into a tower defense turned out to be way more fun than I expected.

So it's two genres in a trench coat. Somehow it walks.

Hoovering up XP with your mouse

Here's the detail I'm weirdly proud of. You don't walk over XP orbs, because there's nobody to walk. The whole game is mouse-only. Instead, orbs are pulled toward your cursor by an inverse-square "gravity", the same falloff as real gravity, with a hard cutoff at about 2 world units so distant orbs don't teleport across the map.

The upshot: you collect XP by waving your mouse around near the orbs, hoovering them up like a magnet. It sounds silly written down, and it feels great in the hand. Move the cursor into a cluster of fresh kills and watch the orbs come streaking in. That single interaction does a lot of work to make a hands-off tower defense feel physical.

Controls beyond that are minimal: place towers, collect XP, and a speed button that cycles 1x / 2x / 3x. The whole simulation scales with it (audio doesn't, so at 3x everything is very fast and the music is very calm about it).

Towers show up on a timer

You don't buy towers from a shop with gold. You start every run with a single Gun tower and that's your whole arsenal. But roughly every 20 seconds a "Tower Queue" charge builds up, and when you spend it the game offers you 3 random tower types. Pick one, and it joins your toolbar to place wherever you like.

On top of that, towers level up from 1 to 9, and the level is shared across every tower of that type, so upgrading your Gun tower upgrades all of them at once. Those upgrades come from the same level-up cards as everything else, which means every card draw is a little tug-of-war between "make my towers hit harder" and "buff the thing I've been neglecting." There are a lot of towers to juggle here, and they get their own post next, so I'll save the roster for post 05.

The waves never stop

This is where the "survivors" half really shows its teeth. There's an authored wave schedule for a while, and then the waves just... keep coming, scaling forever. Enemy HP climbs by roughly 1.15^n once you're past the scripted part, so a run is never about clearing a fixed number of enemies. It's about how long you can hold the line before the math wins.

There's a meta-progression layer bolted on too: medals (bronze, silver, gold, and an endless tier) per stage, saved locally. But that's a rabbit hole for the stages post, so consider this a teaser and nothing more.

Everything you see is a placeholder

Quick honesty break. None of the art is final. All of it is Kenney's free CC0 top-down Tower Defense tileset, reused shamelessly: the Tesla tower is wearing the Frost turret's sprite, most bosses are just a Splitter enemy scaled up until it looks menacing, and the XP orbs are a recolored frost tile. Sounds and music are Juhani Junkala's CC0 packs. The font is "Press Start 2P." Even the name "td-survivors" is a placeholder standing in for a name I haven't thought of yet.

So when future screenshots show a "boss" that is transparently the same little guy as the trash mobs but chunkier, now you know why. It's programmer art all the way down, and I regret nothing.

What's coming

This is the tone-setter, so here's the map of where the series is going. Later posts dig into the towers (all sixteen of them), the enemies that walk the path, the oversized bosses, the stages and their medals, the upgrade cards that make each run feel different, and the tech underneath it all. On that last one: the whole thing runs on an ECS with no classes and no this, just arrays, and there's a whole post about why in post 10.

Next time: sixteen towers, one path, and the eternal question of whether "more Gun towers" is a strategy or a cry for help. See you on the path.