Escape Velocity is a series of games made by Ambrosia Software, a company that still operates by the shareware model. They make games and utilities for the Mac, as well as the occasional port of a PC game. They also ported their latest game in the EV trilogy to the PC. But enough digression.
Escape Velocity, and its successors, is a fairly unique game. The player controlls a spaceship from a top-down 2D view (think Asteroids) and has near-total reign over what he does. One can focus on the trading aspect of the game; most sectors have planets, stations, and the like, where one can buy and sell various commodities. Get enough money and new ships and equipment can be purchased, allowing for greater cargo capacity, better maneuverability, more space for weaponry, and the like. Get a good enough ship and combat becomes viable; pick on someone you don't like and raid them! Killing enemies raises your combat rating, and if you're careful, you can disable enemies instead of destroying them, thus allowing you to raid their stores of money, fuel, and cargo. Of course, fighting the wrong people makes enemies, and you may find your presence in certain sectors actively discouraged. Very dedicated and bored players can ultimately conquer planets, should they choose. Finally, stopping by in the bar or mission center gives you the chance to pick up on various missions (read: quests); this is where the RPG aspect of the game appears. Missions may be simple one-shots: take this special cargo here, destroy this random pirate dude, go get this guy some brandy, et cetera. Or, they may be large, sprawling storylines involving a mixture of exploration, transportation, and fighting. The writing for the three Escape Velocity games has all been quite good, making this part of the gameplay quite pleasurable.
One of the great things about the EV games is that they're modular. With a little work, anyone can make a plugin for the game that replaces any or all parts of the content (including graphics, sound effects, missions, universes, and even the HUD design). In fact, Ambrosia has released total-conversion plugins for EscapeVelocity Nova that convert it into the first two games. (Which, incidentally, allows the EV-deprived, PC-using masses to play all three.) Because of this, the games take a very long time to lose replayability value, since there are a huge number of minor-tweak plugins and quite a few total-replacement plugins available for download from the games' websites.
One of my favorite games involved watching a Rebel fleet duke it out with a Fed cruiser, then ducking in with my shuttlecraft and commandeering the cruiser once it was disabled. Lessee...shuttle crew complement is 1; cruiser gets about 1000 people, right? Damn I'm spiffy.
SeleneTan insists that it is impossible to control any inertial ship in EscapeVelocityNova? and thus refuses to complete any part of the game other than those involving Vell-os ships. (Which are psionically created and therefore non-inertial.) Er... most ships will continue moving in their current direction unless a force is applied (they have inertia!), but the ship head can point in any direction. This supposedly makes it easier to drift by an enemy ship and target it with guns for the entire drift. Vell-os ships, on the other hand will always head in the direction the ship is pointing, and can be decelerated all the way down to a complete stop. SeleneTan has found herself almost completely unable to land inertial ships while being shot at, whereas landing amid combat is only slightly more difficult when using an inertialess ship.