I personally think this is brilliant. It was bought for me as a present by my Girlfriend for my Birthday, and I love it. Streets of Rage was one of my favourite Sega Mega Drive games, so I was glad that was on there, as well as Alien Storm and Sonic and Knuckles (I personally prefer this to the original). As said by another reviewer, the original Sonic isn't on this so that should be changed. And as said by the same reviewer, I was a bit gutted the original Golden Axe wasn't on here, as that is also one of my favourite games on the Sega and (going back a bit) the Amiga. Although I have enjoyed playing the second one, and it is very challenging after a couple of levels.
Another thing I enjoy about this is the fact that I have grown to really enjoy some of the games, even though I haven't played them 'til now. Altered Beast is one of my favourites on there, although quite basic, it is also quite tough after a couple of levels, and each new level brings a new creature for you to transform into. Shadow Dancer is very fun, one hit and you are dead, so you have to be careful and not rush in, the last boss is impossible! Eswat is quite good but I've not got past the second level, as it's not as enjoyable as the other games. Jewel Master is another game I have discovered. You get new rings during levels or after bosses and different combination's do different things, and when you get a new one you have to pair it up with your old ones and see what it does. It's another sidescroller but it's quite refreshing as with new rings you get new abilities and magic so you don't have to use the same old moves over and over. My favourite at the moment is Fatal Labyrinth, a very basic RPG, where your character is in a dungeon and each square is only revealed when he steps into it, your goal is to get items, kill the monsters, find the stairs, and go up them to the next level. Each time you play the game everything about the levels is different, so it's a new mini adventure each time, very enjoyable for short and long periods.
The other games have either not held my attention or I've hardly played them, however I will get round to trying them out soon.
Another feature which makes the item great is the cable to plug into your TV. As I play this a lot at home I can plug it into my TV, and it really is like playing a Sega Mega Drive again, graphics are exactly the same and sound is really good too, not to say they are not on the handheld screen, it just brings the games to life more on the TV.
The downsides are possibly the picture being a bit grainy sometimes, but for less than 30 pound, and games a bit younger than me, and 18 of them, you can't really complain. And it is only slightly noticeable on bright games like Sonic, but even then it's never got in the way of my enjoyment. It's hardly noticeable and if you plug it into your TV the picture is perfect.
And it is a bit light, not a huge problem I just worry how much of a knock it could take.
The only other downside is the lack of multiplayer. Obviously not a lot could be done about this, but with games like Streets of Rage and Alien Storm I always found it was good to have a mate to bash them with. But as many of the games are single player and the ones I mentioned are still really good played single player, it's not really a problem.
Also maybe it's the batteries I used, but I've played many hours on this on the first batteries I bought and it hasn't ran out yet, things like this usually burn through batteries very quickly but this doesn't.
In closing, I'd say if you long for the good old days of gaming, and wish to rekindle childhood memories of great games or play classics you might have missed, buy this handheld console!