Space invaders extrekme is pretty darn good for a space invaders game. The best variation of it I've ever played in fact. It's still not *that* good though.
It is very fast and frantic but a little easy until it gets very hard where it becomes impossible quite quickly. Its a sorta pick up and play for 15 mins then don't touch for a while type game. You're not going to be sinking in hours at a time thats for sure just to let you know.
Star Ocean is a pretty good remake of the old snes one but again its nothing special. Its an extremely basic RPG, the combat is god damn awful, I don't know if you've played SO3 on the PS2 but its kinda how that would play if we went back a 1000 years.
Imagine comparing the original "pong" to a modern tennis game like top spin 2\3. It really really spoils it. The backgrounds are quite nice and its quite polished but it feels old fashioned to me and not in the good sense.
I haven't actually finished it to be honest but I'm a good 25 hours in and i understand the game is 30 hours long roundabouts and I can tell i'm at the last bit of the story.
If you want an RPG I'd give a game called PoPoLoCrOiS a shot, its a port of a PS1 rpg containing both the original and its sequel in a "back to back" type game, so it seems like 1 game.
Its really really good, it feels classic not outdated like Star Ocean does. You got to appreciate Star Ocean really is one of the 1st SNES RPGs to offer decent graphics from the chrono trigger era...
I'd download a ROM for the snes and have a quick go to make sure you don't get dissapointed with your purchase.