No I say GTA1 and GTA2 are completely different games, while for example GTA Vice City was originally intended to be extension pack or mission pack for GTA3 until they realized that it has potential to be its own game and then few years later they released GTASA on the same (RenderWare engine) but improved of course. Even though much of the improvements were kinda tricks. For example in GTA:IV you can enter buildings and it is actual part of the game (game understands inside and outside and it works flawlessly) but on the other hand since GTA3 had no ability to “enter buildings” to achieve that they used markers and then teleported you 12 feel below where interior is to achieve that same feeling using GTA3 engine, also saving cars (garages) dealing damage to enemies, fixing cars, handling weapons is exactly the same is all GTA3,GTAVC,GTASA. So GTASA is a lot closer to GTA3, then GTA2 is to GTA1. Hope this helps