Catacomb Snatch

Catacomb Snatch is a game developed in sixty hours by Mojang as part of a Humble Bundle Mojam charity event, with all proceeds from development going to charity. Before the event, there was a poll for what genre and setting the game would be, with the highest and lowest votes in the respective categories being the final decision in which to develop the game. Given the results, the game is a Shoot'Em Up RTS set in Steampunk Ancient Egypt.

The objective of the game is to collect enough money make your way to the center of the map, connect the base and the center with a railroad and place carts to transport the essence of the center back to your home base. All that must be done by defending your structures.

In addition to Catacomb Snatch itself, buying the Bundle also gave access to the game's source code. This has led to the very rapid growth of a community based around modding the game by adding additional features and fixing bugs that came with the release version. Several different versions of the game are now available, it's quite likely that over time these versions are going to become even more distinct and varied from each other.

Tropes used in Catacomb Snatch include:

Cartoon Bomb: These can be bought.
Flash of Pain: When hurt, enemies flash white.
Game Breaking Bug: When Coin Collectors are destroyed, the game crashes. Naturally, this is the first thing modders fix.
Hearts Are Health
Level Editor: Not directly but practically; the level the game uses is generated by a simple 16x16 pixel image file, and is easily editable with Paint. At least one modded version has added in a level editor into the game itself, and the ability to choose between multiple levels is one of the most common features added to the game.
Made of Explodium: Enemies explode upon destruction, though this causes no noticeable damage.
Money Spider: Enemies contain a surprising amount of treasure when killed, particularly the snakes considering their lack of limbs.
Mook Maker: There are sarcophagi which create enemies.
Power-Up Magnet: The natural ability variety. Treasure close to the player is automatically collected when not firing.
Ragnarok Proofing: The interior of the tomb is in pretty good shape for an ancient Egyptian tomb, other than the monsters and occasional holes in the floor. Indeed, other than the destroyable wall tiles the structure seems no worse for wear despite your constant shooting and use of explosives.
Regenerating Health: The players, your placed items, and the enemies all regenerate health.
Sentry Gun: These can be bought.
Shows Damage: The color-change variety. Enemies and placed buildings turn redder when damaged. Some mods have added in visible health bars.
Treasure Is Bigger in Fiction