Norris2k on 08 May 2014
They really manage their licenses:
- high standard of quality. Even one shitty game can kill a license. Most other characters were ruined by declining quality or shitty games (see what happened to Sonic)
- good release timing. Not too much games that get a fans bored, not so little it's forgotten.
- use of the character as a guest star and free advertising in lot of games (mario kart, etc.)
- as a result of all 3 above, enough fans to make any release a success
Also, in lots of genre with declining success, one and only one game title remains as a famous and massive worldwide sale. For example, civilization for turn based strategic game, street fighter for fighting games. For platform game, Mario is the One.
