Let's establish straight away that this little indie game is a distraction. It's a puzzle duel of words that's good for a laugh, but don't expect to be swept away by any deeper mechanics or much entertainment beyond the silliness it offers.
So what is Oh...Sir! The Insult Simulator all about then? Well, basically you're trying to poke fun at another character's weak spot (be it their appearance, age, or family), while creating combos by being repetitive (a proven method when it comes to insults), and trying to build lengthy, grammatically correct (not always sensical) sentences. You can play against the AI, but it's preferable to find a friend to insult (either locally or online).
The concept itself is very entertaining, as evident by the success of the free game jam version of the title that preceded this commercial release. There are some nice references in there, whether it's the Monty Python parrot bit, or that you can use Windows Vista or Batman v Superman in an insult. Simply put, you'll smile, chuckle and laugh while playing this game, at least for a while.
You have a pool of ten phrases or words that each player take turns choosing from, additionally there are two phrases or words than only you can use at the bottom. You can refresh these two by drinking tea (which spends your turn). If you can't finish a sentence grammatically you'll fail so you need to build as elaborate an insult as possible while still being able to turn it into a proper sentence. The game is very good at judging this, and it is also surprisingly good at understanding when an insult really isn't all that insulting. "Your son is your math teacher", doesn't really burn all that much, even if "your math teacher" typically scores as a heavy insult for some reason.
Each character has a weakness, and you need to poke at this weak spot as much as you can in order to create insults that eat away at the health bar (or is it dignity bar?). Some character's weak spots are more difficult to hit than others, and you'll want to snatch up the words and phrases that tie into your own weakness as fast as you can to avoid taking too much damage. The same goes for repetition combos, insulting someone's father three times in a row is apparently a great way to win an insult duel. It's not the most entertaining mechanic though, as whether or not a word or phrase reappears is entirely random.
The two bonus phrases or words that only you yourself can use include some character-specific insults and finishers that are "rude" and give better scores. Lo Wang for instance can say, "so says the Fortune Cookie!" to finish off an insult.
In terms of content there are a handful of characters excluding the Devolver Digital cameos in the shape of Lo Wang and Serious Sam. It doesn't make for tremendous variation, but it is likely that more characters will get added over time adding more variation and value. Given their various weaknesses, they're not perfectly balanced. Serious Sam for instance, his weakness is "nothing too serious", which kind of defeats the whole purpose of the game as most everything is silly (expect for the queen, of course).
There's not a huge amount of stuff here to keep you engaged for an extended period. The vocabulary is limited, there aren't a great deal of arenas or characters, and you'll progress through each of the character tournaments in about 30 minutes or thereabouts. The lasting appeal is multiplayer, but even that is limited by the scope of the game. But if you consider the price of admission, a couple of quid, that's perfectly reasonable. You'll get a couple of entertaining hours out of the game before it starts to get a bit tedious, and you'll likely want to sling some insults when a friend comes over, but probably not more than a match or two, possibly three. An editor to create your own quirky characters with weaknesses and catch phrases would be a massive improvement on what's there at the moment. Particularly for multiplayer purposes.
Overall, we'd recommend Oh...Sir! The Insult Simulator if you're looking for a quick and fun, but not terribly deep distraction.