Desktop Tower Defense was first released on March 3rd 2007, this was version 1.0, and since then versions 1.2 and 1.5 being released on March 21 2007 and June 22 2007 respectively.
The goal of the game is to destroy creatures which are trying to get past your towers, which you slowly but surely build as you advance through the levels of the game, depending on which difficulty you choose Easy, Medium or Hard, the creeps you face either have more health or there are more creeps to face each level. As the player progresses through the level the creatures they will face will have more health, the way they destroy the creatures is by having more powerful towers.
- Pellet Tower - These are the basic tower and can attack both ground and air creatures. They can eventually be upgraded to a Sniper Tower. Usually these are used for maze building, as they are the cheapest tower.
- Squirt Tower - These are quick firing towers that can attack both land and air creatures. They can eventually be upgraded to a Typhoon Tower
- Dart Tower - These are slow firing towers that can only attack land creatures. They can eventually be upgraded to a ICBM Tower
- Swarm Tower - This is a fast firing tower which fires 4 missiles and can only fire at air creatures. They can eventually be upgraded to a Storm Tower
- Frost Tower - This tower slows creatures down when they fire a missile at them, it can hit multiple creatures with one shot. They can eventually be upgraded to a Blizzard Tower
- Bash Tower - This tower only damages the ground around it, when it attacks it has a chance to stun the creatures so they can not move. They can eventually be upgraded to a Quake Tower
- Ink Tower - This tower has a maximum and minimum range, the tower shoots blobs of ink at the ground which damages creatures when they walk over it. They can eventually be upgraded to a Ink-Blot Tower
- Snap Tower - This tower fires only once and damages an area around it, the tower can attack both land and air. They can eventually be upgraded to a Spike Tower
- Boost Tower - This tower does not shoot but instead boosts the damage of the towers around it.
Creeps are the enemies you have to kill. They give player extra money after being killed, allowing him/her to build or upgrade towers.
- Normal - Just normal creeps, nothing special.
- Immune - Like normal, but won't be slowed by Frost Towers.
- Group - All creeps are packed together.
- Fast - Like name says, they are fast.
- Spawn - When killed, 2 lower health creeps come out. (In case of boss version, the creeps divide again)
- Flying - These creeps fly over towers, won't be shoot at by ground-only towers.
- Dark - These creeps have armor, reducing damage they take from towers.
- Morph - They change between above creep types (expect flying) after some time.
There are boss versions of above creeps, when 1 of given type (expect group, in which case 3) come out from entrances. They have increased health and value.
A Nintendo DS version, developed by Frima Studio in conjunction with THQ, was released in May 2009. It featured new graphics (from DTD 1.9, which was in development at the time), a simple art editor (in which player can draw creeps and towers) and an in-game achievement system.