Super Robot Wars Scans
It is actually really great looking at all those robots from different anime fight together in one game. (It probably costs Banpresto tons of money to buy all those licenses from different anime creators)
The difficulty and the length of the game varies greatly upon the title as well. Titles may vary from 3X episodes to 100+ episodes and the last boss may be killed with 1shot to a boss who can endure hundreds of attacks (maybe)
The game system is quite similar throughout the series except for minor(?) changes. The battlefield looks like a map of a SRPG with small robots all around the map. When you attack an enemy with a weapon, it changes to a 1 vs 1 (or until 1 vs 4 for Alpha 2) screen where one robot attacks and the other robot counters/evades/defends.
As a fan of the games, I've seen both TV series and the OVA (disliked many of the character design changes in the second series). I preordered the recent US rerelease of the OVA and TV series, but am still waiting for them to get delivered, even though the official release date was 7 weeks ago . . .
The first series (Divine Wars) is pretty bad and repetitive, and misses a lot of important events from the game; they could have tried a lot better than that. The second (The Inspector) looks a bit better as of now, but I can't say anything else until it ends... The games are great, by the way; and one of my most important references as for the mecha genre