If arriving at Petrzalka, you will need to catch a bus to the city centre and you will need to buy a ticket. I had to do so from the little shop at the railway station a couple of years ago which fortunately was open. However the lad serving on didn't speak English or German and so I had to show him a picture of the particular ticket I wanted that I had downloaded from the internet.
My previous visit was in 1976 on a youth hostelling holiday. I had got a one-day visa from the Czechoslovakian embassy in Vienna and bought a return ticket. The two lads I was travelling with refused to accompany me. There were just two trains each way per day. On arrival at the border between Marchegg and Devinska Nova Ves, a nice lady official made me change some money into Czech crowns and told me I would need to return early the next day. Border guards then literally took my compartment apart, even unscrewing and removing the ceiling panels.
On arrival in Bratislava, every lamppost and building had two flags, one Czech and one Soviet. I almost got into trouble for boarding a trolley bus without a pre-purchased ticket, but a local took pity on me and sold or gave me one. I then went looking for the Slovan Bratislava football ground, who I had seen play a friendly at Bradford in 1965. I was surprised to find a second ground nearby, the home of Inter Bratislava, and saw a poster saying they were playing VSS Kosice that very evening. This posed me a dilemma. Should I stay overnight and catch the morning train to Vienna, thus overstaying my 24-hour visa by a couple of hours, or should I walk to the border sooner, or should I go back to Vienna that afternoon and miss the game? Eventually I decided to risk it.
Not knowing if there was a youth hostel in Bratislava, I went into the rather grand Carlton Hotel and asked how much it was to stay the night. Not having enough Czech crowns, I asked if they took English money. The receptionist's eyes opened wide with delight and she cranked the handle of her vintage calculator a number of times and said FOUR pounds! It was luxury after all those youth hostels.
Inter won 4-0, I risked the train the next day, and didn't get arrested. But on arrival in Vienna, the train was greeted by Austrian guards with machine guns and my mates were less than enamoured when I returned to the youth hostel a day late.
A few years earlier, two different friends from Bradford went to see England play Czechoslovakia in Bratislava. They were based in Vienna and had one-day visas. Unfortunately for them, the game was abandoned due to fog and they had to go back by bus to Austria. They were not allowed back when the game was replayed the next day.