Sega has started to release free mobile versions of classic games from its back catalogue.
The first five, including Sonic the Hedgehog, are available now via the Apple and Android app stores.
The gamemaker said it planned to release additional titles every two weeks for the Sega Forever service.
Some fans have complained about the first releases, saying Sega has done a poor job of converting the classic titles to mobile devices.
“Above all else Sega Forever is a celebration of nostalgia,” said Mike Evans, head of Sega’s mobile division in San Francisco in a statement. “It’s about allowing fans to reconnect with past experiences.
“It’s a very easy conversion to take those games to free,” Mr Evans told games website GamesIndustry.biz.
As with many other apps, Sega said it would run ads before and after the games were played. However, it said it would make it easy for players to avoid them.
“We’re just bolting in the advertising support model and a single in-app purchase that can disable those ads,” Mr Evans added.
Sega said it would cost $1.99 in the US and £1.99 in the UK to turn off the ads.
The online gaming catalogue will eventually feature titles from all the Sega console eras. Initially Sega said it was concentrating on games for the Master System, Mega Drive and Game Gear consoles but those made for the Dreamcast and Saturn would follow.
The first five games on Sega Forever are:
- Sonic the Hedgehog
- Comix Zone
- Phantasy Star II
- Kid Chameleon
- Altered Beast
Games can be played via a portable device’s touchscreen or by a controller. Sega said they would also be playable offline but people can save their progress online if they wish. The games firm said it would eventually add a multiplayer option to many of the games.
But not all fans of older games were happy with the arrival of Sega Forever. Retro games enthusiast John Linneman criticised the way they had been transferred or ported to mobile devices.
He said the “lousy emulation” led to glitches during gameplay.
“There are loads of dropped frames, hitches and skips,” Mr Linneman told games website Nintendo Life. “And when a notification occurs, it gets much worse. So it never plays smoothly.”