The movie games are handled by four different studios. The PS3/360/PC games are handled by two different studios, but seem to be exactly the same in terms of content, they try to follow the events of the movie to a certain extent. The PS2/Wii games are somewhat different (I haven't seen how much different since the PS2/Wii games have been considered to be horrendous), and are handled by a different studio then the HD versions. The DS versions are handled by one studio seperate from the others and is a completely different experience, instead of playing as your favourite Autobot, or Decepticon, you make your own Autobot, or Decepticon and join up their ranks. The PSP version tends to hardly follow the movie at all, and does it's own thing, done by a different studio as well. Since I don't have any more then just the HD version, I'm solely speculating based on the first movie's games.
I have a few G1 figures (Astrotrain, Optimus Prime 25th Anniversary Edition, a Starscream), not sure about Soundwave (I know I have the Cybertron version though). Hasbro re-released G1 Soundwave as a Toys"R"Us exclusive like only last year, you may be able to find a legit (ie, a non-bootleg version) pretty easily on like Ebay, Kijji, or something (if you want, post a topic on Cybertron.ca and if anyone has another one laying around...). And there is always the ROTF Soundwave which is clogging store shelves right now!