'Aussie Rules' is different again from Rugby, but we have both Rugby Union & Rugby League here, as well as the true Aussie game, Aussie Rules!!
The Rugby Union we play here, mainly in the Eastern States altho to a smaller extent elsewhere, is pretty much the same game they play in the UK - 2x40 minute halves of pretty much non stop sprinting, big boys, no pads or helmets, heavy hits, lotsa loose & sometimes rolling scrums inc racking boots over a downed player with the ball, line outs every now & then, the only real breather anyone gets is when the backs get a chance to sprint in to form up on a downed tackled player, but generally the play goes on; it is a tough game & can be a fairly exciting & very physical game to play, but it's a little less so to watch unless you are a Rugby Union fan.
Rugby League is played a lot in the Eastern States too but hardly anywhere else, & it's much more of a viewers game (& has been modded to suit TV broadcasts a lot more) - still 2x40 minute halves of pretty much non stop running, no real padding (altho that is changing) way more scrums & heavy hits but once a player is tackled & downed it's time for everyone to back off & start again - due to the 'hands & boots off the tackled player' & the frequency/number of scrums they have, Union players (& I gotta admit I come from a family of them) have been known to describe it as 'one man trying to push two men's heads up three men's arses!' But it is an extremely physical game, they are still big boys & the padding they wear is minimal, and they take some massive hits only to hafta get up again & sprint on to form up in the moving play that continues unabated!!
Aussie Rules is a 'more refined' game, played pretty much country wide (hence the 'true Aussie game') with 4 quarters of 20 minutes non-stop play plus extra time for out of bounds etc. It has fewer heavy tackles, way more running, lotsa loooong kicks - in fact kicking the ball is the major way of moving play around the larger field. Due to the kicking & marking that makes this such a fast game (moving from end to end in seconds, not minutes!) it has been called 'aerial ping pong', but honestly, it's a bloody hard game to play, much harder to play well, and in just about every test that's ever been conducted (& there've been a few) Aussie Rules player come out on top as being the fittest & most flexible players of the 3 games. They are still big boys, don't wear padding, & take some heavy hits just to get up & sprint on, but the 'tackles' the other two games see are sorta frowned upon here & tend to be largely avoided by the player passing (kicking or punch hand-passing) the ball off & then chasing it down.
I'm not saying that your 'Gridiron' players aren't big fit blokes, nor that they don't take big hits, there is no denying that they are & they do, but back during my college days (loooong ago now - & the older I get the better I was!) I played Regional Rugby Union & District Aussie Rules plus a little recreational League, and then when I joined the Military I spent some on exchange postings playing inter-service Gridiron, so I have some feel for them all; and IMO your game has much more emphasis on the strategy & plays, while the 3 Aussie games are much more physical ALL the time for ALL the players on the field, have fewer substitutes & less time off the field (if any) & basically, if you are on the field, you are running, mostly sprinting, & either kicking or getting tackled pretty much all the time!!
That said, I've got nothing but respect for all the players that get to the highest level of their chosen game, & I really don't want to pick a fight with any of them; but hey, I enjoyed the games I played but couldn't ever really stand watching any of them if I wasn't playing - driving/riding or watching others drive fast cars & trucks was far more my style! Still is! :thumbup: