(1) NO TILT: If a planet has no tilt it has no seasons. On every part of the planet the Sun is up for half a day then down for half a day, and day and night are equal length. At the Poles the Sun circles around the horizon forever. At the Equator it rises vertically at the East point on the horizon, passes directly overhead, then sets vertically at the West point on the horizon. At mid-latitudes it rises at the East point on the horizon, but at an angle to the vertical which is equal to your latitude; passes North or South of overhead by an angle equal to your South or North latitude; then sets at the West point on the horizon at the same angle that it rose at the East point.
Since the Sun follows the same path every day, any given place on the planet receives the same amount of solar heating every day. This does not mean that there are no temperature variations on the planet. There are still day/night variations, climatic zone variations, and daily or weekly variations in the weather due to, e.g., changes in cloud cover (presuming there are clouds). For example, on Mercury it can be as much as 800 degrees above zero Fahrenheit at the Equator in the early afternoon (about 7 Earth weeks after sunrise), but close to zero Fahrenheit near the Pole. If you were standing in the sunlight near the Pole you'd get very hot — almost as hot as at the Equator — but in the shade, where only the light reflected by surrounding rocks heated you, it would be relatively cold (in fact some craters have bottoms in permanent shade, and temperatures there are close to absolute zero).
(2) TILT LIKE OURS: Seasons would be similar to ours other than differences due to their distance from the Sun. Thus Mars, with a tilt similar to ours, has the same seasonal changes as the Earth, but since Mars is further from the Sun all its seasons are colder than ours, and since its larger orbit entails a longer orbital period, all its seasons are longer than ours.
(3) EXTREME TILT: On the Earth there are extreme seasons at the Poles, where the Sun is up for half a year, then down for half a year, but it never gets very warm (i.e., it is always arctic), because the Sun is always low in the sky. At the Equator there are hardly any seasons, and it is always warm (i.e., it is always tropical), because the Sun is up exactly half a day every day of the year, and passes fairly close to overhead every day of the year, so that it shines down on the ground about the same every day of the year.
For planets with an extreme tilt, however, as the Sun moves further and further North it gets higher and higher at the North Pole, and on Uranus, the Sun can be nearly overhead at the Pole for years on end (since the half "year" that the Sun is up is 42 Earth years), making it substantially warmer than the Equator ever gets (where the Sun is only nearly overhead for an hour or two). Meanwhile, at the Equator, since the Sun is close to the celestial North Pole, which is at the North point on the horizon (this is true at the Equator on ANY planet), it is very low in the sky, providing less than 1/10th the heat per hour that it is providing the Pole at that time (particularly during the half-day when it is down!).
SUMMARY: So on planets with no tilt there are no seasonal variations — just day/night and climatic zone variations. On planets with tilts similar to ours the seasons could be warmer and shorter if the planet were closer to the Sun (though none are), or colder and longer if the planet were further from the Sun (as all are), but seasons would be similar to ours — namely, no seasons worth speaking of at the Equator, extreme seasons but always arctic at the Poles, and middling seasons such as we are familiar with, at mid-latitudes. And on planets with extreme tilts, the Poles can become warmer than the Equator, and the Equator can become colder than the Poles. Of course, the fact that the only planets with such tilts never get warmer than 300 degrees below zero Fahrenheit somewhat spoils the concept of "warmer" and "colder", but the variations are still real.